A Simple, Low-Tech Trick For Keeping Your Greenhouse Warm (and Cool)

Since it’s been cold lately, I’ve been doing a lot of thinking about frost protection and growing species appropriate to my area, as well as pushing non-appropriate species to grow. (I’ve got an avocado death race going right now; believe it or not, I still haven’t lost any despite multiple freezes.)

Along those lines, I just posted a new article over at Mother Earth News on how I keep my greenhouse from freezing overnight without using any electricity or gadgets:

“When I set up the greenhouse for the first time, I was excited to feel how hot it got inside as soon as I zipped the doors and windows shut. I loaded it up with all my cold-sensitve plants, then put a thermometer inside so I could keep an eye on the temperature.

Within the next few days, there was a frost predicted. The night of the frost, I shut up the greenhouse and went inside. Late at night I went out to check the thermometer. It was almost as cold inside the greenhouse as it was outside! That wasn’t good. I quickly strung up a bunch of Christmas lights, plus a few flood lamps, then plugged it all in via an extension cord.

The next morning when I went outside after breakfast to open up the greenhouse, the sun was shining brightly and it was quite warm when I stepped inside. Too warm. I checked the thermometer – it was already reading in the 90s. Uh-oh. I needed to really stay on top of my venting or I was going to cook something! So I did, diligently shutting the greenhouse on chilly nights and quickly opening it again in the morning once things had warmed up.

It came to me then. I remembered reading that some folk in tough climates used walls of water-filled barrels to absorb the heat of the sun during the day. At night, the warmth would radiate out from the barrels and keep things moderate inside. I decided to try it in my greenhouse. A friend of mine had a source for 55-gallon plastic drums so I bought eight of them and placed them at regular spacings along both walls of the greenhouse, then filled them to the top with water and screwed the bungs closed (read the rest here)

Sometimes it doesn’t take a giant complicated system to make a big difference. Growing something out of its range can be as easy as planting it in a different place or using the cover of existing trees to shelter new trees.

In this case, I spent $20 each for 8 barrels for a grand total of $160.00. That small investment has kept me from having to spend money on electric, plus it’s kept me from worrying about my plants roasting during warm days when I forget to open the greenhouse because I’m online, writing an article for The Prepper Project and…